(CNN) -- The idea of volunteering away from home seems like a win-win to many travelers: a way to experience and help another community at the same time. But without a solid, well-designed program and reasonable expectations, volunteer travel can do more harm than good.

Showing up in parts unknown, hoping to make a big difference in a small amount of time, is likely to leave travelers and hosts disappointed.

"You're not going to change the world in a week or two. You're not going to eradicate poverty in a village. You're not going to teach a kid how to read," said Doug Cutchins, a former Peace Corps volunteer and co-author of "Volunteer Vacations: Short-term Adventures That Will Benefit You and Others."

The key to having a positive impact in a short amount of time is realizing that your efforts are part of a process, Cutchins said. Results are subtle and come about slowly through a long line of volunteers.

"Development is a tricky process, and as Americans we are very, very product-oriented," he said.

He's concerned with what he calls "development by monument," where volunteers want a completed building or another physical representation of their volunteer efforts to answer the inevitable "what did you accomplish?" question from friends and family at home.

"That's one of the first questions you're going to get asked, and it's hard sometimes for people to say, 'well, I was kind of part of a process, and we engaged in cultural exchange.' But that's really the very best way to do it," Cutchins said.

Daniela Papi agrees. She is one of the founders of PEPY, a non-governmental organization dedicated to educational development in rural Cambodia. PEPY Tours hosts learning trips that help fund the group's projects.

The organization has gone from referring to those trips as "voluntourism" to calling them "edu-tourism" or "educational adventures."

"The number one thing that's going to happen is that you are going to have a new perspective on your country, on your life, on your choices and how they affect the world, on what it means to live in whatever country that is," Papi said.

The 10 days or so spent traveling and learning would ideally inform participants' choices and outlook at home, where they will have the largest impact, Papi said.

Teaching English and construction projects are the most common types of voluntourism projects Papi sees in her region. Travelers involved in a construction voluntourism project should ask the operator and organizations involved about the plans for the structure when the volunteers go home, she cautions. Who is going to take care of it, who will work in it, how will they be trained, and who will fund the training?

A poorly constructed school without trained teachers isn't likely to have the benefits volunteers envision. And in the case of teaching English, who will teach the children when there are no volunteers, and what effect does a revolving-door model of teaching have on kids?

Successful projects start with the needs of the community, voluntourism organizers say.

"We don't go in and say, 'this is what your problem is, and this is how we're going to fix it,' " said Catherine McMillan, a spokeswoman for Globe Aware, a nonprofit that develops short-term volunteer programs.

Members of the community should be involved in identifying and addressing areas where partner organizations can help.

The organization you're working with should have a strong and ongoing relationship with the community, local non-governmental organizations and project leaders on the ground.

"It's a complicated kind of tourism, because you don't want to send folks and do something and then not have, not measure the consequences of that action in the long term," said Erica Harms, director of the Tourism Sustainability Council, an initiative involving the United Nations and travel partners.

Travelers should ask about the program's history and its involvement with NGOs or other organizations. Find out where the funding is coming from and where it is being allocated. Ask about how the project is supported over time and how the community was involved in its development, Harms said.

And keep in mind that organizing volunteers to help support these efforts is not free. There are costs associated with housing and feeding volunteers, with transporting them locally, with training them and establishing a system of working that allows visitors to contribute for a short period.

Most of Globe Aware's programs require a contribution fee of approximately $1,200 per week, which does not include airfare. PEPY Tours cost $500 to $700 a week, plus a fundraising or donation minimum of $500 for individuals.

PEPY Tours participants are giving back mostly through their financial support -- which is what will keep the education projects running, Papi said. But visitors can see where their money is going and may have an opportunity to get physically involved.

Cutchins says reputable organizations will be up-front about costs, what is included and where your money will be spent.

Globe Aware's McMillan recommends looking up nonprofits on Guidestar.org, which compiles tax forms from nonprofits, to see how operators are spending. It's also a good idea to contact past volunteers or people who are familiar with the organization's work on site.

Travelers should be realistic about what would make for a positive experience and select opportunities that fit their skills and interests.

"I think there are very few people who would make really bad volunteers. ... It's really about matching the right person with the right opportunity," Cutchins said.